Solid state/class d vs tube amps

[JimmyM]

It's really the fact they break down, it's more a matter of realiability. As they mention in the interview, they tend to sound a bit diferent everytime.

Greatly exaggerated IMHO, although I guess I could see it if they're cranking them hard enough to wear tubes out after one or two shows.

 

[seamonkey]

usually SS amps have "mixed mode feedback" which does the same thing as tubes do in respect of xformer-speaker interaction.. mixed mode feedback is hard to implement in high power class D amps (because most of them are bridged amps).. in that case, a resonant 2 pole hpf (chebishev, mfb, state variable,etc) tuned to the desired "speaker resonance" (you need to check the speaker datasheet).. the Q around 4 or 5..will help with the "tube uuumph", and a slight boost on the 2-4khz zone followed by a sharp HPF will give "warmth".. Tube dynamics under distortion is a different story, and much more difficult to emulate..but you can get away with a limiter or compressor..

I don't know. I see a lot of marketing of magical musical negative feedback schemes. Negative feedback is really there in the amp part, to counteract interaction to artifacts caused the load. Good amp sections and cabinets are there to follow the signal they are fed. Simple negative feedback lets an amp accomplish this. The class-d module and chip makers add this into their designs. Extra magic added in a feedback path just seems like marketing. More of a made up problem, with a fancy solution to try and differentiate one offering from another.

I believe to get a good processed signal to the amp section and let it do it's job. There is still negative feedback loop form the musicians ear, to brain, to fingers. That is the real global feedback!

Tube dynamics are being emulated now. The spice models match the actual hardware. The signals null. It's not a future thing - It's now. Try the amps in Amplitube. Amplitube and other modelers start with the schematic and a golden reference hardware version of the amp. This is used later to null the signal. Schematics built in the spice models. These don't get away by adding compression, they are the same signals. They null with the original. That is just a starting point as the modeling can do so much more.

There's plenty of others modelers, even ones that look like hardware like the Axe and Kemper. These hardware looking ones seem to be a gentler intro for some people. I'm looking forward to seeing what musicians do with the with having so much more than ever before.

 

[seamonkey]

Please don't tell the audiophiles this. They are willing to play $2400 for a matched pair of 60w power triodes.
The component count on SS amps is significantly higher than a tube amp. You would have to be crazy, and some of us are, to build a point to point amp.
IMO, bass amps and audiophile amps are more similarly designed than say guitar amps and bass amps.
Regarding features, SS design is simpler because of PNP and NPN technology. Tubes have only one flavor.

But FETs don't have a PN or NP junction. Funny thing is FETs actually predate BJT. AT&T was denied some patents on transistors because of existing previous patents. It took a while, but amps using field effect devices are everywhere now.

 

[Drgonzonm]

I am not here to argue with you. As I am sure not all FET's have both PN and NP designs. You will find two links to a couple of the common FET's that have PN and NP junctions. Do the FET's now being used in amps have the PN and NP design? I don't know. My engineering training took place at the end of the tube era. Some of my electrical engineer books have reference to tube design as well as BJT applications.

But FETs don't have a PN or NP junction. Funny thing is FETs actually predate BJT. AT&T was denied some patents on transistors because of existing previous patents. It took a while, but amps using field effect devices are everywhere now.

FET is a generalized term for field effect transistor. which includes:
JFET, MOSFET (There are more than 20 types of FETS)
PN and NP for JFET.
Invalid Link Removed
PN and NP for Mosfet
Invalid Link Removed

 

[seamonkey]

I am not here to argue with you. As I am sure not all FET's have both PN and NP designs. You will find two links to a couple of the common FET's that have PN and NP junctions. Do the FET's now being used in amps have the PN and NP design? I don't know. My engineering training took place at the end of the tube era. Some of my electrical engineer books have reference to tube design as well as BJT applications.



FET is a generalized term for field effect transistor. which includes:
JFET, MOSFET (There are more than 20 types of FETS)
PN and NP for JFET.
Invalid Link Removed
PN and NP for Mosfet
Invalid Link Removed

Yes - right
I should have added on the main current carrying path. Just like they are drawn in schematics.

 

[Drgonzonm]

What do you mean by 'neutral'? That a PA will closely reproduce with little coloration the inputs its given? That's fine, but if it were just about 'adjusting the volume to the room' then anyone could be a sound guy. There is lot of post input processing and equalization going on before it hits the speakers.

You hit my definition of neutral on the nose. reproducing with little colorization. Mic'ing an existing amp, saves lots of time for the sound guy.
If I have a choice, I prefer DI from my bass. the sound guy can't make silk from my sow's ear playing.

 

[pigpen1]

You hit my definition of neutral on the nose. reproducing with little colorization. Mic'ing an existing amp, saves lots of time for the sound guy.
If I have a choice, I prefer DI from my bass. the sound guy can't make silk from my sow's ear playing.

Cool. I guess what I meant though, is there is still gonna be some channel string EQ tweaking, low/high filtering compression etc. Flat and push the fader up isn't always going to work with finding spots in a mix.

 

[svtb15]

I am working with an American idol artist right now. He uses the Kemper on tour.
What he did was he brought his vintage boutique collection of amps into the studio in Nashville and modeled his amps.
I'll be damned if anyone could tell the difference between the real deal amp and the Kemper with your eyes closed.
I thought it was a novelty for him. But nope, he swears it even has the feel of his real amp when mic'd.
I Love it because the stage volume is fairly LOW. FOH loves it too..

There's plenty of others modelers, even ones that look like hardware like the Axe and Kemper. These hardware looking ones seem to be a gentler intro for some people. I'm looking forward to seeing what musicians do with the with having so much more than ever before.

 

[Drgonzonm]

To be fair I think the Electar was SE, but maybe it would have worked if working very gently. I never got as far as detaching it from the internal speaker and trying it on a bass cab.

The Electar 10 is a two tube SE amp. Would it play bass? I don't know, You don't need to detach the internal speaker and hook it up to a bass cab. Just plug in the bass. and strum your low string. If it sounds, then maybe it can be used for a bass practice amp. IMO, you risk blowing out the speaker. It is possible you might cook the the O/T.
I have a M8e Rickenbacker SE amp, it is not capable of handling a bass. It was designed for a Hawaiian guitar. Its worth more than the list price of one of my basses.
I also have a 4 watt SS amp, that I won't try playing my bass through it. Even though I paid $3.00 for it and had to find a power supply, I bought it so I have a small amp for my mini-squier.

 

[Drgonzonm]

Cool. I guess what I meant though, is there is still gonna be some channel string EQ tweaking, low/high filtering compression etc. Flat and push the fader up isn't always going to work with finding spots in a mix.

No argument from me.

 

[-Asdfgh-]

The Electar 10 is a two tube SE amp. Would it play bass? I don't know, You don't need to detach the internal speaker and hook it up to a bass cab. Just plug in the bass. and strum your low string. If it sounds, then maybe it can be used for a bass practice amp. IMO, you risk blowing out the speaker. It is possible you might cook the the O/T.
I have a M8e Rickenbacker SE amp, it is not capable of handling a bass. It was designed for a Hawaiian guitar. Its worth more than the list price of one of my basses.
I also have a 4 watt SS amp, that I won't try playing my bass through it. Even though I paid $3.00 for it and had to find a power supply, I bought it so I have a small amp for my mini-squier.

I played bass quietly a couple of times, just to see how it performed, but didn't rewire the speaker. It was OK if played with very little gain. It might have been passable at low volume through a large speaker. I used to use my YBA-1A for playing guitar through as much as bass, but then it was too loud.

 

[agedhorse]

PA's by design are neutral. It doesn't matter whether its a guitar amp, or bass amp, The band or individual playing sets up the sound the way they want, and the board person, then adjusts the volume to the room. Everybody's happy. I spoke to my favorite sound guy Mark Enriquez.

But that's not how it typically happens. As often as not, the sound on stage is SO different from the house that what sounds good on stage does not translate which is why many FOH guys take a DI (either pre or post depending on what they need to do) and a mic. Generally, they will get the majority of the bass from the DI and then add mic (if needed) to flavor and texture. The eq and makeup of the bass in the house mix may appear quite different from what's happening on stage, but if you were to listen to listen to the bass in the house it would sound more like the bass on stage than the mic alone would. Now before you argue with me, or throw your favorite sound guy at me, I spend over 30 years at FOH in venues from 1000 - 5000 seats, supporting mostly national acts. At the smaller club level perhaps this may be more true, but the acoustic environments are much smaller.

.... And swapped to SS amp and emulation for the reason I explained earlier

Not true... much of the migration of such acts to digital modeling is due to the difficulty and hassle of maintaining a very complex signal path with multiple processing devices, switching, cabling, amps, etc. By modeling everything and building the presets from the models, it's possible to greatly reduce the potential for failure throughout the system. The amps themselves are not as much of an issue as all oft he other stuff happening. Many of these rigs are quite complex with 40 or 50 inter-related components. We have guys at the factory who are quite involved with this stuff at the touring and support level. Of course, these complex systems are not very common except at the "money is no object" level, but since you quoted an act that we actually work with, my comments are accurate.

But FETs don't have a PN or NP junction. Funny thing is FETs actually predate BJT. AT&T was denied some patents on transistors because of existing previous patents. It took a while, but amps using field effect devices are everywhere now.

I am not here to argue with you. As I am sure not all FET's have both PN and NP designs. You will find two links to a couple of the common FET's that have PN and NP junctions. Do the FET's now being used in amps have the PN and NP design? I don't know. My engineering training took place at the end of the tube era. Some of my electrical engineer books have reference to tube design as well as BJT applications.

FETs don't have gate junctions (in the same sense that BJT's have). FETs have channels, and there are N channel and P channel FETS of all kinds.

 

[NecroticImbecil]

My only experience with Kempers comes from 2 recent concerts. At one, an opening act had one on stage. Assume the guitarist was using it, They sounded excellent. At another, the main act had 2. Worst sounding concert I've ever been to. Heartbreaking, band was full of fantastic musicians. Guitar was a bit tinny and resplendent with pick and string noise. Bass was weak and honky, all upper mids. fortunately they were buried in the mix, hard to hear over vox and keys. Even the drums were feeble. I wondered if there were any subs working until they keyboard player hit a low note that almost triggered a quake. The latest tech can sound just as terrible as anything that has come before it, incompetence conquers all.

 

[agedhorse]

The latest tech can sound just as terrible as anything that has come before it, incompetence conquers all.

Or, it can sound as good as anything. Just like any bass, it's all about how well it's played.

 

[Korladis]

Sounds like my reaction when I first discovered the Mesa Subway D800! But then again I've never played through a tube amp. I just can't imagine the hassle of moving it around and constantly changing tubes. But if you can try a Mesa Subway, it's about as tubey as you're going to get from a small class D amp.

Constantly? I've retubed my Mesa D-180 (power tubes only, not preamp tubes) twice in the seven years that I've owned it. And I play doom metal, so I'm cranking it into the red pretty frequently.

 

[Anachronism]

I don't know. I see a lot of marketing of magical musical negative feedback schemes. Negative feedback is really there in the amp part, to counteract interaction to artifacts caused the load. Good amp sections and cabinets are there to follow the signal they are fed. Simple negative feedback lets an amp accomplish this. The class-d module and chip makers add this into their designs. Extra magic added in a feedback path just seems like marketing. More of a made up problem, with a fancy solution to try and differentiate one offering from another.

I believe to get a good processed signal to the amp section and let it do it's job. There is still negative feedback loop form the musicians ear, to brain, to fingers. That is the real global feedback!

Tube dynamics are being emulated now. The spice models match the actual hardware. The signals null. It's not a future thing - It's now. Try the amps in Amplitube. Amplitube and other modelers start with the schematic and a golden reference hardware version of the amp. This is used later to null the signal. Schematics built in the spice models. These don't get away by adding compression, they are the same signals. They null with the original. That is just a starting point as the modeling can do so much more.

There's plenty of others modelers, even ones that look like hardware like the Axe and Kemper. These hardware looking ones seem to be a gentler intro for some people. I'm looking forward to seeing what musicians do with the with having so much more than ever before.

I have amplitube. It’s $hit compared to real tube amps.

 

[Korladis]

Nokia phones....

Power tube wear out pretty fast..they can last a couple of years if used at home..but if used regularly at venues, they last about a year...

I go years between retubes and I play in two doom metal bands. Basically cranking up the amp near as loud as it will go, overdriving the power tubes every gig and every rehearsal. I go a few years between retubes, and likely would have gone longer had the amp not fallen during a tour.

They don't wear out after a year, though. And I don't need to buy a whole new set of transistors if I drop one on the concrete.

Tubes don't wear out after a year, in my experience.

And if you drop an SS amp on the concrete, you may have to buy a whole new amp.

No it's not

+1

In my experience it's actually easier to find tube amp techs than it is to find techs for SS amps.

I don't think it's a myth if you gig a lot and move your amp a lot.

It's absolutely a myth. I gig in very loud bands. I put hard use on my amp. I don't retube until power tubes fail, and that definitely takes longer than a year to happen.

I admit I based my point of view on my feelings, but also on the last Metallica's rig rundown where both guitar techs explain they only now use AxeFx and Matrix SS power amp.
Because "it's way more reliable, always sounds the same and can handle heavy touring, unlike tube amps"

And yet when they were touring most heavily, they used tube heads.

Using AxeFx is likely to integrate amplification and effects into one component rather than a number of different components that could all fail.

 

[JimmyM]

But that's not how it typically happens. As often as not, the sound on stage is SO different from the house that what sounds good on stage does not translate which is why many FOH guys take a DI (either pre or post depending on what they need to do) and a mic. Generally, they will get the majority of the bass from the DI and then add mic (if needed) to flavor and texture. The eq and makeup of the bass in the house mix may appear quite different from what's happening on stage, but if you were to listen to listen to the bass in the house it would sound more like the bass on stage than the mic alone would. Now before you argue with me, or throw your favorite sound guy at me, I spend over 30 years at FOH in venues from 1000 - 5000 seats, supporting mostly national acts. At the smaller club level perhaps this may be more true, but the acoustic environments are much smaller.

I'll pass on debating this go-round because I find the next paragraph way more interesting. At least for tonight. But we'll come back to it eventually, I'm sure

Not true... much of the migration of such acts to digital modeling is due to the difficulty and hassle of maintaining a very complex signal path with multiple processing devices, switching, cabling, amps, etc. By modeling everything and building the presets from the models, it's possible to greatly reduce the potential for failure throughout the system. The amps themselves are not as much of an issue as all oft he other stuff happening. Many of these rigs are quite complex with 40 or 50 inter-related components. We have guys at the factory who are quite involved with this stuff at the touring and support level. Of course, these complex systems are not very common except at the "money is no object" level, but since you quoted an act that we actually work with, my comments are accurate.

Have you seen their rig video for this year? They don't do Rob but they do James and Kirk (Kirk's tech said something that makes me believe Rob's doing Axe-FX, too). They use two Axe-FX's each because they don't want any gaps at all when switching sounds, and using two and switching them manually was the only way they could make it happen. A whole new set of baggage with these things? Haven't they got that perfected to the point where there are no gaps when switching between sounds? Also, James' tech talked about how James likes to stand near the two Mesa 412 cabs he has on stage to get himself settled.

$5 says they're back with a wall of amps by the end of the year

 

[agedhorse]

The modeling, with 2 rigs is a simple and practical approach. Ham and Egging it between the two units does insure zero delay switching but as important maintains a hot backup at all times.

For their specific needs it is efficient and practical even if it isn't perfect.

 

[baxter_x]

The modeling, with 2 rigs is a simple and practical approach. Ham and Egging it between the two units does insure zero delay switching but as important maintains a hot backup at all times.

For their specific needs it is efficient and practical even if it isn't perfect.

What is perfect?